DIY plotter with laser

[Viacheslav] built a plotter that is fast and accurate. He wanted to take it one step further and added a laser in place of the pen. The 300 mW unit does a nice job of wood-burning any pattern sent to it, but isn’t strong enough to serve as a laser cutter for anything other than thin-film. We wonder if it can be used to cut solder paste stencils for surface mount PCB production.

In the video after the break you can see some plotting that uses a pen. In addition to writing on paper, [Viacheslav] has tested this as a method of applying etch resist to a copper clad board for PCB production. He’s able to achieve 0.8 mm pitch but the production process is limited by the resist pen’s tendency to wear out quickly and to only prevent etching for a short period of time (compared to toner transfer resist).

5W costs like 5 hundred bucks on ebay, it’s from Australia, I think and being shipped everywhere…

Btw, this machine shares same conception and idea of that one with hot wire we saw recently in here…
I’m building my own laser plotter out of 2 broken dvd-roms and 300mW laser I took from the ‘RW’ one :)

I should have my 3-axis ‘plotter’ done in a few weeks as well. The design is based off the gantry platform for a Rhino robotics teaching platform with some slight (heavy) modifications. Should be pretty sweet when it’s done..

That’s some nice plotting there. Even just the pen. Sounds pretty cool too.

Though I wonder if he couldn’t dust a copper clad board with toner and get the laser to melt it to form a resist layer (and not damage the board!). The only limit then is the .8 mm pitch, since that’s a little over 30 mil. It might solve the ink running and short pen life issues.

Could also do it printer-style, just sweeping back and forth.
But where’s the fun in that?

Definitely showing my laser ignorance here but I was wondering if you could use a beam combiner do up the oomph of the laser. There was a RGB laser hack not too long ago where some one made a “white” laser using parts from a broken PSP. Would it be possible to replace the other two colored laser with ones of the same color to get more bang for your buck?

It’s a 300mW laser module found on eBay. Comes as a kit with a simple LM317-based driver, without modulation input. I didn’t bother modding it: the laser is relatively weak so I just move the head much much slower where I want it to leave the trace and move it with normal warp speed between the vectors. It’s fun to engrave wood and crispy breads and you can cut shapes out of black foam. For PCB making though, no, not really.. It could be a lot of fun, but traditional photoresist method is just so much more precise, easier and perhaps faster.

@polymath: You can buy power combiners, but they’re fiber based, so you’ll have to have fiber-coupled laser diodes as well as a way to cleave/align/fuze the fibers. Despite the equipment costs, it’s much easier to accomplish with fiber than in free-space.

Hey, has anyone here been fool-hardy enough to pick up a ebayed laser bar, or fibre diode and hook it up to a yag crystal… Project probably around $1200 mark power output probably 80-300Watts before the Crystal. I’ve heard if you do it, too much, you’ll go blind.

@Paul: Nd:YAG emission at 1.06 micron is particularly dangerous, since it is impossible to see without an IR viewer and is often high power (in the case of a YAG laser).

You’d do much better with a flashlamp pumped Nd:YAG, but you’ll be limited to maybe 10Hz repetition rate, so your average power will be quite low (maybe a watt at best). The power in each pulse will be pretty high though..

maybe you could cover pcbs with a paint made out of toner powder (you’d make it with starch or gelatine, isoprop, and water- like for photo paper or inkjet overheads)
then the laser could be used on the black copper surface: melt the plastic traces, wash of the rest, etch

@Andrew; 0.8 mm is not a very fine trace. The Motori itself has a PCB with traces ranging from 0.3 (narrow places near fine-pitch IC’s) to 0.4 (general signals) up to over 1mm (power busses) wide.

Re: precision in general: the motors can position very finely, stepping at some 0.2mm I guess (they are different on two axes so I have different calibration in the firmware). But the end precision you get on paper is a sum of belt play, drive play, bridge play and oscillations, pen holder play etc.. The results are consistent though.

If anyone really would want to make something practical out of a project like this, it would be a foam or stencil cutter for RC models, or small signs, something like that. With a 300mW laser the orders are not going to be very quickly served, too ;)

ive been trying to do the same with my Roland A3 plotter, i have 300mw red laser, it will etch 30 thou black styrene card though 10 thou would be better, the idea was to make stencils as mentioned b4, two things i need to do, slow down the plotting speed it moves too fast, and a fan to blow away the smoke, the beam is defused by the smoke and optical power is reduced, also i think a laser higher up into the IR spectrum would work better

High accurance is useless with leadscrews who backlash a lot. The cheap one usually do that. Belts are much better than cheap leadscrews, but the torque/force will be lower. Get a bigger motor, The resolution increases if one use gearing to get more power but it’ll be slower.
(use belts to avoid backlash)

Improve resolution:
Higher step/degree at the motors.
gearing. use belts.
leadscrews. preferably with zero backlash.
(or cheap treaded with bolts/nuts, but the accurancy will go down compared to belts)
Or belts with microstepping/1.8 degrees motors
lower frictions at the bearings (?)
Smaller and slower is a cheap way.

Probably a really stupid thought but I must admit ignorance here. As for the wood burning, would it be possible to have say~~~ two laser diodes(such as from a dvd writer) both aimed in the same spot on the wood and be able to move a bit faster? (obviously this is assumed that the entire surface to be burned would be flat and level)?????
I have a cnc machine and would really really like to be able to burn designs in wood like this but I don’t know much about lasers.

It’s going at 1cm/minute on slightly darkish wood, I guess. I never measured and I have it packed away for now, to provide space for other stuff. Those lasers can be found on ebay for whereabouts of $40 with shipping, you can buy one just to experiment: for the geeky type it’s one of the best ways to spend $40 imho :) Practical side of this is dubious, unless you do some decor/handcrafts stuff, like adding ornaments to kitchen boards.